China Daily. China will shift from corn to sorghum, cassava and sweet potato as feedstock for bio-fuel over the next five years. Cassava and sweet potato both are high-yield plants, and though edible, are not used as a staple food.

Part of the government’s efforts to develop bio-fuel without harming general food supply and security, the shift will ensure a healthy supply of corn both as food and fodder.

Xiong Bilin, deputy director of the National Development and Reform Commission’s (NDRC) industry department, told China Daily that the conversion of the four major ethanol production centers, which have a combined output of 1 million tons, will neither be too complicated nor costly.

The existing four corn-based facilities have already been joined by a cassava-based unit in the Guangxi Zhuang Autonomous Region that can produce 200,000 tons of ethanol a year.

China is also about to approve construction of its largest-yet ethanol plant. The facility in Hengshui in Hebei Province is expected to produce 300,000 tons of biofuel, mainly from sweet potato, every year.

Another ethanol plant in Jingmen, Hubei Province, will produce 200,000 tons of ethanol from sweet potato plants each year.

China wants to increase its ethanol production from 1 million tonnes (333 million gallons US) a year to 2 million tons (667 million gallons US) in 2010, and 10 million tons (3.3 billion gallons US) by 2020. Currently, gasoline and diesel sold in nine provinces is mixed with 10% ethanol.

The government is considering a 5% tax rebate to ethanol producers, and some financial subsidies both to the producers and suppliers.

It is purely for energy supply (or energy security for that matter). Ethanol won't drastically improve air pollution either. If anything it might increase VOC emissions which would further contribute to smog, since ethanol-gasoline blends are more volatile than gasoline alone.